11th World Congress on Computational Mechanics (WCCM XI) 5th European Conference on Computational Mechanics (ECCM V) 6th European Conference on Computational Fluid Dynamics (ECFD VI) E. Oñate, J. Oliver and A. Huerta (Eds) A NUMERICAL INVESTIGATION OF SCRAMJET ENGINE AIR INTAKES FOR THE 14-X HYPERSONIC VEHICLE AUGUSTO F. MOURA * , MAURÍCIO A. P. ROSA * * Instituto de Estudos Avançados (IEAv) Departamento de Ciência e Tecnologia Aeroespacial Trevo Cel. Aviador José Alberto Albano do Amarante, 1, 12.228-001, São José dos Campos, Brasil e-mail: augustofontan@gmail.com, www.ieav.cta.br Key Words: hypersonic flow, scramjet intake, performance parameters Abstract. This work is part of the research and development, at the Institute for Advanced Studies (IEAv), of the first Brazilian hypersonic vehicle prototype, the 14-X airplane. It presents CFD results and performance calculations of the air intake section of some scramjet engine configurations under several operating conditions assuming 2D planar geometry. The reference case considers the vehicle flying at Mach 7 and zero angle of attack at an altitude of 30 km. In this case, air compression is achieved by two ramps, one of which is the vehicle forebody itself and the other is a scramjet inlet compression ramp, and the engine cowl which satisfies the “shock-on-lip” condition. From this reference case, several other cases were simulated varying vehicle operating conditions such as altitude, velocity and angle of attack. Besides these, calculations were made for different configurations of the scramjet inlet compression geometry by varying the inlet compression ramp angle, as well as the number of inlet compression ramps. The airflow in the intake is calculated numerically with the commercial Ansys Fluent software, considering the air as a calorically perfect gas for inviscid flow. For the intake performance analysis, several parameters characterizing the intakes have been calculated and compared. 1 INTRODUCTION The Institute for Advanced Studies (IEAv) is currently developing the 14-X Airbreathing Hypersonic Vehicle with scramjet engine propulsion, capable of flight at hypersonic speeds (M>5) at high altitudes. As part of the ongoing effort and due to a lack of significant numerical analyses of the flow conditions at flight, a number of CFD analyses have been performed using the commercial solver ANSYS Fluent. A scramjet (supersonic combustion ramjet) is a variant of a ramjet air-breathing combustion jet engine in which the combustion process takes place in supersonic airflow. As in ramjets, a scramjet relies on high vehicle speed to forcefully compress and decelerate the incoming air before combustion (hence ramjet), but whereas a ramjet decelerates the air to subsonic velocities before combustion, airflow in a scramjet is supersonic throughout the entire engine. This allows the scramjet to efficiently operate at hypersonic speeds (Mach >5):